Obtaining a multi-modal route through a multi-modal transportation network presents certain challenges. Such transportation networks typically include sub-networks of different types, i.e. associated with different modes of transport. These differences in the properties of the different types of network make it difficult to generate a multi-modal route across both types of network, as a routing engine cannot easily operate on both types of network. Routing algorithms tend to be specific to a certain type of transportation network. Current attempts to obtain a multi-modal route involve exploring the different networks separately to determine routes therethrough. For example, a route may be determined from a departure point through a network associated with one mode of transport to a departure point for another mode of transport, and then a route from the departure point for the other mode of transport to the destination determined through a network associated with the other mode of transport.
By way of example, a multi-modal transportation network may include a public transportation sub-network, and a transportation sub-network for use by private transport, e.g. a road network (a “private transportation sub-network” as referred to herein). These types of network have different properties. Times of entry, exit and travel through a public transportation network are constrained, such that entry, exit and travel through the network may only occur at specific times, i.e. in accordance with a schedule associated with the network. In contrast, such constraints do not exist in relation to a private transportation network, such as a road network, when using private transport. In a private transportation network, a user may choose to enter, exit or travel through the network freely, at a time of their choosing.
Private transport routing algorithms, e.g. car routing algorithms, and public transportation routing algorithms tend to differ mathematically as a result of the different properties of such networks, with the consequence that they cannot readily be integrated to provide a true multi-modal route planner. Previous attempts to obtain a multi-modal route involving both road and public transport networks have tended to involve using a first routing algorithm to find a route through the road network from an origin to a closest point of interchange with the public transport network, and then using a second route planner for the public transport network to find a route from the interchange to a destination. There is increasing interest in being able to generate multi-modal routes, e.g. to allow a user to integrate their use of private transport and public transport between an origin and destination of interest, to provide a more efficient overall journey, and/or to reduce environmental impact.
The Applicant has realised that there is a need for improved methods and systems for generating routes through a multi-modal transportation network, in particular where the network includes a first sub-network where times of entry, exit and travel through the network are constrained, such as a public transportation network, and a second sub-network which is not so constrained, such as a road network.